Temperature dependence of photoconductivity and recombination in hydrogenated amorphous silicon

The recombination processes in undoped hydrogenated amorphous silicon under steady-state illumination have been studied in order to explain the temperature dependences of photoconductivity. The recombinations of free carriers through the exponential tail states and through the Gaussian distributed dangling bond states were calculated in terms of the Shockley-Read theory and the occupation statistics of correlated defects. An additional recombination of trapped electrons and holes in the tail states through the dangling bonds by tunneling should be included in order to explain the experimental data of the activated photoconductivity at low temperatures.